BMI Calculator: How to Calculate and Interpret Your Result

What Is BMI?

Body Mass Index (BMI) is a number calculated from your height and weight that categorises you into underweight, normal weight, overweight, or obese ranges. It is widely used by healthcare providers as a quick screening tool.

BMI = Weight (kg) ÷ Height (m)²

Example: 70 kg, 175 cm (1.75 m)

BMI = 70 ÷ (1.75 × 1.75) = 70 ÷ 3.0625 = 22.9 (Normal weight)

BMI Categories

BMI Range

Category

|---|---|

Below 18.5	Underweight
18.5 – 24.9	Normal weight
25.0 – 29.9	Overweight
30.0 – 34.9	Obese Class I
35.0 – 39.9	Obese Class II
40.0 and above	Obese Class III

BMI Limitations for Indian Populations

Research has consistently found that South Asians (including Indians) have higher body fat percentage at the same BMI compared to Western populations. The risks for diabetes and cardiovascular disease begin at lower BMI levels.

Several medical organisations recommend lower BMI cutoffs for Asian Indians:

Overweight: BMI ≥ 23 (instead of 25)

Obese: BMI ≥ 27.5 (instead of 30)

BMI Does Not Account For

Muscle mass: Athletes with high muscle mass can have a high BMI while having very low body fat. Muscle is denser than fat.

Age: Older adults naturally have more fat mass relative to muscle.

Gender: Women have higher healthy body fat percentages than men at the same BMI.

Fat distribution: Where fat is stored matters. Belly fat (visceral fat) is more dangerous than fat stored elsewhere. Waist circumference is a better predictor of metabolic risk.

Better Health Metrics to Track

Waist circumference: Risk increases at >90cm for Indian men and >80cm for Indian women.

Waist-to-height ratio: Waist should be less than half your height.

Body fat percentage: Measured by DEXA scan, bioelectrical impedance, or skinfold calipers.